1. Field of the Invention
The present invention relates to a liquid resin composite molding technique that uses spaced apart flexible diaphragms for receiving a fiber reinforcement and a mold such that the reinforcement mat holding diaphragms are vacuum pressed into the mold.
2. Background of the Prior Art
Fiber reinforced composite materials are an important class of engineering materials that offer outstanding mechanical properties and unique design flexibility. Such materials are lightweight, corrosive resistant, impact resistant, and exhibit excellent fatigue strength. Composite materials are used in a wide variety of applications including automotive parts, aviation, marine vessels, offshore structures, containers and piping, and sporting goods among others. Liquid composite molding, which includes resin transfer molding, reaction injection molding, and resin infusion, is one of the most attractive manufacturing solutions for producing high quality, affordable, and environmentally friendly composite materials.
Recently, a considerable amount of progress has been achieved in liquid composite molding techniques such as constituent material development, tooling, reinforcement preform development, curing control, and process simulation. These advances have lifted the liquid composite molding process to new heights.
One major hurdle that continues to receive considerable attention concerns the costs of liquid composite molding. In most techniques, the part being made is formed between an upper mold and a lower mold. Each of these molds is very costly and the molds are very time consuming to produce. Additionally, as the resin contacts the surface of the molds, each mold must be cleaned and prepared between cycles. Furthermore, the resin flows into the cavity between the molds in three dimensions. This three dimensional resin flow makes flow control complicated and increases the potential for end product defects due to dry spots. As defective parts cannot be repaired, they must be discarded adding to the overall manufacturing costs of the products being produced.
Therefore, there exists a need in the art for a liquid composite molding technique that reduces overall manufacturing costs and decreases product defect potential. Specifically, such a technique must eliminate the need for one of the molds used to manufacture a part and the single mold being used should be relatively easy to produce and must not need to be prepared between cycles. The technique must eliminate the need for the three dimensional resin flow currently used in other prior art techniques in order to reduce overall manufacturing complexity and also to reduce the potential for product defect.